Eight new planets have been discovered in the 'Goldilocks' zone of their stars, orbiting at a distance where oceans and life could exist.
科學(xué)家已經(jīng)發(fā)現(xiàn)了8個(gè)新的可能有海洋和生命的行星。它們位于這些行星的恒星的適居帶內(nèi)。

The discovery doubles the number of small planets less than twice the diameter of Earth which are believed to be in the habitable zone of their parent stars.
該發(fā)現(xiàn)使直徑不到地球兩倍、被認(rèn)為位于它們母恒星可居住帶內(nèi)的小行星數(shù)量翻了一倍。

Among these eight, astronomers say there are two that are the most similar to Earth of any known exoplanets to date.
天文學(xué)家說(shuō)，在這8個(gè)行星中，有兩個(gè)是迄今已知所有外行星中和地球最像的。

'Most of these planets have a good chance of being rocky, like Earth,' said lead scientist Dr Guillermo Torres, from the Harvard-Smithsonian Centre for Astrophysics in Cambridge, US.
美國(guó)劍橋大學(xué)哈佛-史密森天體物理學(xué)中心首席科學(xué)家吉列爾莫·托雷斯博士說(shuō)：“這些行星中的大多數(shù)都很可能像地球一樣有巖石。”

The two most Earth-like planets, known as Kepler-438b and Kepler-442b, both orbit red dwarf stars that are smaller and cooler than the sun.
那兩個(gè)最像地球的行星分別是Kepler-438b和Kepler-442b。它們都繞紅矮星軌道運(yùn)行。這些恒星（紅矮星）不僅比太陽(yáng)小，還比太陽(yáng)冷。

With a diameter just 12 per cent bigger than Earth, Kepler-438b has a 70 per cent chance of being rocky, the scientists have calculated.
科學(xué)家估計(jì)，直徑只比地球長(zhǎng)12%的Kepler-438b有巖石的幾率是70%。

Kepler-442b is about one-third larger than Earth, and the likelihood of it being rocky is around 60 per cent.
Kepler-442b只比地球大三分之一，有巖石的幾率約是60%。

To be in the habitable zone, also known as the 'Goldilocks zone', a planet must be not too hot or too cold and receive roughly as much sunlight as Earth.
如果一個(gè)行星處在可居住帶內(nèi)，就必然不太熱或不太冷，還會(huì)像地球一樣受到充沛陽(yáng)光的照射。

Too much heat from its star, and any water would boil away as steam. Too little, and the water would freeze solid.
如果行星從恒星那里得到過(guò)多熱量，行星上的任何水都會(huì)像蒸汽一樣蒸發(fā)。如果得到的熱量太少，水就會(huì)凍成固體。

'For our calculations we chose to adopt the broadest possible limits that can plausibly lead to suitable conditions for life,' Dr Torres added.
托雷斯表示：“為了計(jì)算，我們選擇使用了似乎都可以導(dǎo)致適和生命存在條件的最廣泛的限制標(biāo)準(zhǔn)?！?/div>

Kepler-438b receives about 40 per cent more light than the Earth giving it a 70 per cent probability of having a habitable zone orbit. In comparison, baking hot Venus has twice as much.
考慮到Kepler-438b有一個(gè)可居住帶軌道的幾率是70%，這個(gè)行星受到的太陽(yáng)照射可能比地球多了約40%。相比之下，非常炎熱的金星受到的太陽(yáng)照射可能是地球的兩倍。

Co-author Dr David Kipping, also from the Centre for Astrophysics, said: 'We don't know for sure whether any of the planets in our sample are truly habitable. All we can say is that they're promising candidates.'
研究負(fù)責(zé)人之一同時(shí)又是哈佛-史密森天體物理學(xué)中心科學(xué)家的大衛(wèi)·基平表示：“我們不能確定我們樣本中的任何行星是不是適于居住。我們只能說(shuō)它們是很有希望的候選者。”

Neither of the planets are our close neighbours. Kepler-438b is located 470 light-years from Earth while the more distant Kepler-442b is 1,100 light-years away.
這兩個(gè)行星都不是地球的近鄰。Kepler-438b距地球470光年，而更遠(yuǎn)的Kepler-442b距地球1100光年。

The team, whose findings were presented at the American Astronomical Society's annual meeting in Washington DC, studied planetary candidates first identified by Nasa's Kepler space telescope.
這個(gè)科研組研究了美國(guó)宇航局開(kāi)普勒太空望遠(yuǎn)鏡最早識(shí)別的行星候選者。改組的科學(xué)家還在華盛頓舉行的美國(guó)天文學(xué)會(huì)年會(huì)上提出他們的發(fā)現(xiàn)。

All the planets were too small to confirm by measuring their masses. Instead, they were validated using a computer program that determined they were statistically likely to be planets.
所有這些行星都太小，所以不能通過(guò)測(cè)量它們的質(zhì)量進(jìn)行確認(rèn)。但科學(xué)家用一個(gè)決定它們?cè)诮y(tǒng)計(jì)學(xué)上可能是行星的電腦程序進(jìn)行了這項(xiàng)工作

After the analysis, follow-up observations showed that four of the planets were in multiple star systems.
分析后，后續(xù)的觀測(cè)結(jié)果顯示，這些行星中有4個(gè)處在多重星系中。

The research is also published in the Astrophysical Journal.
《天體物理學(xué)雜志》刊登了該研究。